screen = pygame.display.get_surface()
font = pygame.font.Font(None, 40)

font_surface = font.render("original", True, pygame.Color("white"));
screen.blit(surface, (0, 0))

screen.fill(pygame.Color("black")) # erases the entire screen surface
font_surface = font.render("edited", True, pygame.Color("white"));
screen.blit(surface, (0, 0))